This invention relates to steady rests employed to support a cylindrical workpiece for precision machining or grinding. More specifically, this invention relates to a multi-point, true centering steady rest having internal cams for adjusting the center position of a supported rotating workpiece, both horizontally and vertically.
Steady rests are commonly used to support rotating cylindrical workpieces for machining or grinding. Steady rests may be found in several of my prior United States Patents, including: U.S. Pat. No. 5,285,599 issued Feb. 15, 1994, for “Method for Adjusting a Steady Rest Having an Internal Centerline Adjustment”; U.S. Pat. No. 5,237,780 issued Aug. 24, 1993 for “Steady Rest with Internal Centerline Adjustment”; U.S. Pat. No. 5,058,468 issued Oct. 22, 1991 for “Remote Gage Steady Rest Heads”; U.S. Pat. No. 4,647,100 issued Mar. 3, 1987 for “Parallel Gripper with Roller Supported Gripper Arms”; U.S. Pat. No. 4,647,097 issued Mar. 3, 1987 for “I.D. or O.D. Parallel Gripper”; and U.S. Pat. No. 4,399,639 issued Aug. 23, 1983 for “True Centering Steady Rest”.
Typically, a steady rest includes a housing mounted on a suitable base adjacent the workpiece. A body in the housing is slidably movable toward or away from the horizontal axis (centerline) of the workpiece, by a hydraulic cylinder or other means of actuation. Gripping (clamping) arms are slidably mounted in a crisscross pattern on the body and move with the body. A wear pad or roller is attached to the outer ends of each of the two arms, and a third wear pad is attached to the body. An internal adjustment means permits the three wear pads to cooperate in providing a three-point gripping arrangement for a rotating workpiece.
For a variety of reasons explained in my prior patents, the axis of a rotating workpiece may shift a small distance either horizontally or vertically. My prior patents disclose means for adjusting the wear pad locations for a horizontal change in the workpiece axis, without adjusting the steady rest housing.
A need exists for independently making either a vertical adjustment or a horizontal adjustment of the wear pads without having to adjust the position of the entire steady rest.
The broad purpose of the present invention is to provide an internal camming device for independently adjusting either the vertical or the horizontal position of the wear pads or rollers. The preferred embodiment employs two internal camming devices each connected to an adjusting screw. By rotating both adjustment screws in the same direction, the camming rails force one clamping arm in one direction and the other clamping arm in the other direction thereby resulting in a vertical adjustment of the imaginary clamping center of the clamping arms. Turning the adjusting screws in opposite directions moves the guide rails such that one clamping arm moves horizontally in one direction, and the other clamping arm moves horizontally in the other direction thereby resulting in a horizontal change in the clamping center of the clamping arms.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.